Alpha-alkylidene and alpha-alkyl cyclo-pentanone



Patented Feb. 9, 1937 UNITED STATES PATENT OF a-ALKYLIDENE AND a-ALKYL CYCLO- PENTANONE Alexander St. Pfau, Geneva, Switzerland, as-

signor to Givaudan-Delawanna, Inc.,

New

Serial No. 748,455. 1933 4 Claims.

I have found that cyclopentanones can be condensed with higher saturated or unsaturated aldehydes to alkylidene cyclopentanones if proper conditions are selected. These new compounds are valuable aromatics, and have a pleasing olefactory odor suitable for perfumes. Cyclopentanones with at least one methylene group in the alpha position and aliphatic saturated or unsaturated normal or branch chain aldehydes with 4 to carbon atoms can be used. The condensation of the two components is effected by the usual alkaline reagents.

The result is either directly the unsaturated ketone or the corresponding e-oxyketone which by splitting 011 water can be transformed into the unsaturated ketone. The products so obtained can be purified either by distillation or by chemical methods, for instance, by the semicarbazones.

By hydrogenation of the so obtained unsaturated ketones the corresponding saturated ketones can be obtained which are also useful as aromatics.

Example #1 Kilo.

Cyclopentanone 1 Ether 15% Caustic soda 1 are cooled to Zero and 1.5 kilo. heptyl aldehyde are added. This gives ,B-o'xyketone: 30

H2o-o0 is obtained, in which the R means C6H13. The

In Germany October 16,

product is a colorless liquid. Boiling point 144 (10 mm.), (1200:0911; n zoo:1,4'79; semicarbazone mp. 185-186".

Example #2 To a solution of Kilo.

Cyclopentanone 1 Alcohol 1 Heptyl aldehyde .7 Caustic soda 35% .05

are added slowly under agitation at -10 C. When the reaction is finished the product is worked up as in Example #1. The yield amounts to 0.5 kilo. of the same product as in Example #1.

Example #3 If caprylic aldehyde is used with either solvent a-octylidene cyclopentanone is obtained. Its composition is represented by the above formula if R is C1I-I15. The boiling point is 165 (10), d2oo:0,905; n 200I1,478; semicarbazone mp. 184- 185.

Example #5 Catalytic hydrogenation of a-heptylidene-cyclopentanone furnished a-heptyl cyclopentanone of the formula e i H2O CH-R HaC-CO where R represents C7H15. Boiling point 130 (10 mm.); 71P20021,453; semicarbazone mp. 184-.

Example #6 In an analogous manner hexylidene-cyclopentanone when hydrogenated gives a-hGXYlcyclopentanone of the formula mentioned in Example #fi'if R=CsI-I13. The boiling point; is consisting of alkyl and alkylidene radicalsrhav- 118 (10 mm); (1200:0387; n zoo:1,450; semiing from 4 to 10 carbon atoms. carbazone mp. 186-187". 2. a-heptylidene cyclopentanone.

The invention claimed is: 3. a-heptylcyclopentanone. 1. A cyclopentanone mono-substituted in the 4. a-hexylidene-cyclopentanone. a-position by a radical selected from the group ALEXANDER ST. PFAU. 

